Engines, including diesel engines, gasoline engines, natural gas engines, and other engines known in the art, may exhaust a complex mixture of air pollutants. The air pollutants may be composed of both gaseous and solid material, such as, for example, particulate matter. Particulate matter may include ash and unburned carbon particles called soot.
Due to increased environmental concerns, exhaust emission standards have become more stringent. The amount of particulates and gaseous pollutants emitted from an engine may be regulated depending on the type, size, and/or class of engine. In order to meet these emissions standards, engine manufacturers have pursued improvements in several different engine technologies, such as fuel injection, engine management, and air induction, to name a few. In addition, engine manufacturers have developed devices for treatment of engine exhaust after it leaves the engine.
Engine manufacturers have employed exhaust treatment devices called particulate traps to remove the particulate matter from the exhaust flow of an engine. A particulate trap may include a filter designed to trap particulate matter. The use of the particulate trap for extended periods of time, however, may enable particulate matter to accumulate on the filter, thereby causing the functionality of the filter and/or engine performance to decline.
One method of restoring the performance of a particulate trap may include regeneration. Regeneration of a particulate trap filter system may be accomplished by increasing the temperature of the filter and the trapped particulate matter above the combustion temperature of the particulate matter, thereby burning away the collected particulate matter and regenerating the filter system. This increase in temperature may be effectuated by various means. For example, some systems employ a heating element (e.g., an electric heating element) to directly heat one or more portions of the particulate trap (e.g., the filter material or the external housing). Other systems have been configured to heat the exhaust gases upstream from the particulate trap allowing the flow of the heated gases through the particulate trap to transfer heat to the particulate trap. For example, some systems alter one or more engine operating parameters, such as air/fuel mixture, to produce exhaust gases with an elevated temperature. Running an engine with a “rich” air/fuel mixture can have such an effect on exhaust gas temperature.
Other systems heat the exhaust gases upstream from the particulate trap, with the use of a burner that creates a flame within the exhaust conduit leading to the particulate trap. For example, one such burner system is disclosed by U.S. Pat. No. 4,641,524, issued to Brighton on Mar. 24, 1987 (“the '524 patent”). The '524 patent discloses a burner system configured to increase the temperature of exhaust gases directed to the particulate trap.
While the system of the '524 patent may increase the overall temperature of the particulate trap, the system of the '524 patent does not include an exhaust outlet configured to direct the exhaust flow out of the burner toward the particulate trap, wherein the exhaust outlet is oriented in a different direction than an exhaust inlet. Further, the system of the '524 patent is not configured to impart rotational motion on fresh air introduced to a fuel injector of the burner to promote an even distribution of the burner flame.
The disclosed burner assembly is directed toward overcoming one or more of the problems set forth above.